Hi,
See module in "steps to reproduce".
When this module is run (DrScheme's run buton) in language MzScheme, all is well.
When it is run in language module, the following is displayed:

(app current-namespace (module->namespace 'x))

Apparently DrScheme uses the redefined #%app for installing the module environment in the interactions window. Is it possible and desirable to make DrScheme use the original #%app for this purpose? If so, I propose DrScheme to be adapted in this respect.
With kind regards and with admiration for the PLT team,
Jos Koot